| 1 | package org.apache.velocity.app; |
| 2 | |
| 3 | /* |
| 4 | * Copyright 2000-2001,2004 The Apache Software Foundation. |
| 5 | * |
| 6 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 7 | * you may not use this file except in compliance with the License. |
| 8 | * You may obtain a copy of the License at |
| 9 | * |
| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 11 | * |
| 12 | * Unless required by applicable law or agreed to in writing, software |
| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 15 | * See the License for the specific language governing permissions and |
| 16 | * limitations under the License. |
| 17 | */ |
| 18 | |
| 19 | import java.io.Writer; |
| 20 | import java.util.Properties; |
| 21 | import java.io.InputStream; |
| 22 | import java.io.IOException; |
| 23 | import java.io.Reader; |
| 24 | import java.io.BufferedReader; |
| 25 | import java.io.StringReader; |
| 26 | import java.io.InputStreamReader; |
| 27 | import java.io.UnsupportedEncodingException; |
| 28 | |
| 29 | import org.apache.velocity.context.Context; |
| 30 | import org.apache.velocity.Template; |
| 31 | import org.apache.velocity.context.InternalContextAdapterImpl; |
| 32 | import org.apache.velocity.runtime.RuntimeInstance; |
| 33 | import org.apache.velocity.runtime.RuntimeConstants; |
| 34 | import org.apache.velocity.runtime.parser.node.SimpleNode; |
| 35 | import org.apache.velocity.runtime.configuration.Configuration; |
| 36 | |
| 37 | import org.apache.velocity.exception.ResourceNotFoundException; |
| 38 | import org.apache.velocity.exception.ParseErrorException; |
| 39 | import org.apache.velocity.exception.MethodInvocationException; |
| 40 | |
| 41 | import org.apache.velocity.runtime.parser.ParseException; |
| 42 | |
| 43 | import org.apache.commons.collections.ExtendedProperties; |
| 44 | |
| 45 | /** |
| 46 | * <p> |
| 47 | * This class provides a separate new-able instance of the |
| 48 | * Velocity template engine. The alternative model for use |
| 49 | * is using the Velocity class which employs the singleton |
| 50 | * model. |
| 51 | * </p> |
| 52 | * |
| 53 | * <p> |
| 54 | * Please ensure that you call one of the init() variants. |
| 55 | * This is critical for proper behavior. |
| 56 | * </p> |
| 57 | * |
| 58 | * <p> Coming soon : Velocity will call |
| 59 | * the parameter-less init() at the first use of this class |
| 60 | * if the init() wasn't explicitly called. While this will |
| 61 | * ensure that Velocity functions, it almost certainly won't |
| 62 | * function in the way you intend, so please make sure to |
| 63 | * call init(). |
| 64 | * </p> |
| 65 | * |
| 66 | * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a> |
| 67 | * @version $Id: VelocityEngine.java,v 1.6.4.1 2004/03/03 23:22:53 geirm Exp $ |
| 68 | */ |
| 69 | public class VelocityEngine implements RuntimeConstants |
| 70 | { |
| 71 | private RuntimeInstance ri = new RuntimeInstance(); |
| 72 | |
| 73 | /** |
| 74 | * initialize the Velocity runtime engine, using the default |
| 75 | * properties of the Velocity distribution |
| 76 | */ |
| 77 | public void init() |
| 78 | throws Exception |
| 79 | { |
| 80 | ri.init(); |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * initialize the Velocity runtime engine, using default properties |
| 85 | * plus the properties in the properties file passed in as the arg |
| 86 | * |
| 87 | * @param propsFilename file containing properties to use to initialize |
| 88 | * the Velocity runtime |
| 89 | */ |
| 90 | public void init( String propsFilename ) |
| 91 | throws Exception |
| 92 | { |
| 93 | ri.init(propsFilename); |
| 94 | } |
| 95 | |
| 96 | /** |
| 97 | * initialize the Velocity runtime engine, using default properties |
| 98 | * plus the properties in the passed in java.util.Properties object |
| 99 | * |
| 100 | * @param p Proprties object containing initialization properties |
| 101 | * |
| 102 | */ |
| 103 | public void init( Properties p ) |
| 104 | throws Exception |
| 105 | { |
| 106 | ri.init( p ); |
| 107 | } |
| 108 | |
| 109 | /** |
| 110 | * Set a Velocity Runtime property. |
| 111 | * |
| 112 | * @param String key |
| 113 | * @param Object value |
| 114 | */ |
| 115 | public void setProperty(String key, Object value) |
| 116 | { |
| 117 | ri.setProperty(key,value); |
| 118 | } |
| 119 | |
| 120 | /** |
| 121 | * Add a Velocity Runtime property. |
| 122 | * |
| 123 | * @param String key |
| 124 | * @param Object value |
| 125 | */ |
| 126 | public void addProperty(String key, Object value) |
| 127 | { |
| 128 | ri.addProperty(key,value); |
| 129 | } |
| 130 | |
| 131 | /** |
| 132 | * Clear a Velocity Runtime property. |
| 133 | * |
| 134 | * @param key of property to clear |
| 135 | */ |
| 136 | public void clearProperty(String key) |
| 137 | { |
| 138 | ri.clearProperty(key); |
| 139 | } |
| 140 | |
| 141 | /** |
| 142 | * Set an entire configuration at once. This is |
| 143 | * useful in cases where the parent application uses |
| 144 | * the Configuration class and the velocity configuration |
| 145 | * is a subset of the parent application's configuration. |
| 146 | * |
| 147 | * @param Configuration configuration |
| 148 | * |
| 149 | * @deprecated Use |
| 150 | * {@link #setExtendedProperties( ExtendedProperties ) } |
| 151 | */ |
| 152 | public void setConfiguration(Configuration configuration) |
| 153 | { |
| 154 | /* |
| 155 | * Yuk. We added a little helper to Configuration to |
| 156 | * help with deprecation. The Configuration class |
| 157 | * contains a 'shadow' ExtendedProperties |
| 158 | */ |
| 159 | |
| 160 | ExtendedProperties ep = configuration.getExtendedProperties(); |
| 161 | |
| 162 | ri.setConfiguration( ep ); |
| 163 | } |
| 164 | |
| 165 | /** |
| 166 | * Set an entire configuration at once. This is |
| 167 | * useful in cases where the parent application uses |
| 168 | * the ExtendedProperties class and the velocity configuration |
| 169 | * is a subset of the parent application's configuration. |
| 170 | * |
| 171 | * @param ExtendedProperties configuration |
| 172 | * |
| 173 | */ |
| 174 | public void setExtendedProperties( ExtendedProperties configuration) |
| 175 | { |
| 176 | ri.setConfiguration( configuration ); |
| 177 | } |
| 178 | |
| 179 | /** |
| 180 | * Get a Velocity Runtime property. |
| 181 | * |
| 182 | * @param key property to retrieve |
| 183 | * @return property value or null if the property |
| 184 | * not currently set |
| 185 | */ |
| 186 | public Object getProperty( String key ) |
| 187 | { |
| 188 | return ri.getProperty( key ); |
| 189 | } |
| 190 | |
| 191 | /** |
| 192 | * renders the input string using the context into the output writer. |
| 193 | * To be used when a template is dynamically constructed, or want to use |
| 194 | * Velocity as a token replacer. |
| 195 | * |
| 196 | * @param context context to use in rendering input string |
| 197 | * @param out Writer in which to render the output |
| 198 | * @param logTag string to be used as the template name for log |
| 199 | * messages in case of error |
| 200 | * @param instring input string containing the VTL to be rendered |
| 201 | * |
| 202 | * @return true if successful, false otherwise. If false, see |
| 203 | * Velocity runtime log |
| 204 | */ |
| 205 | public boolean evaluate( Context context, Writer out, |
| 206 | String logTag, String instring ) |
| 207 | throws ParseErrorException, MethodInvocationException, |
| 208 | ResourceNotFoundException, IOException |
| 209 | { |
| 210 | return evaluate( context, out, logTag, new BufferedReader( new StringReader( instring )) ); |
| 211 | } |
| 212 | |
| 213 | /** |
| 214 | * Renders the input stream using the context into the output writer. |
| 215 | * To be used when a template is dynamically constructed, or want to |
| 216 | * use Velocity as a token replacer. |
| 217 | * |
| 218 | * @param context context to use in rendering input string |
| 219 | * @param out Writer in which to render the output |
| 220 | * @param logTag string to be used as the template name for log messages |
| 221 | * in case of error |
| 222 | * @param instream input stream containing the VTL to be rendered |
| 223 | * |
| 224 | * @return true if successful, false otherwise. If false, see |
| 225 | * Velocity runtime log |
| 226 | * @deprecated Use |
| 227 | * {@link #evaluate( Context context, Writer writer, |
| 228 | * String logTag, Reader reader ) } |
| 229 | */ |
| 230 | public boolean evaluate( Context context, Writer writer, |
| 231 | String logTag, InputStream instream ) |
| 232 | throws ParseErrorException, MethodInvocationException, |
| 233 | ResourceNotFoundException, IOException |
| 234 | { |
| 235 | /* |
| 236 | * first, parse - convert ParseException if thrown |
| 237 | */ |
| 238 | |
| 239 | BufferedReader br = null; |
| 240 | String encoding = null; |
| 241 | |
| 242 | try |
| 243 | { |
| 244 | encoding = ri.getString(INPUT_ENCODING,ENCODING_DEFAULT); |
| 245 | br = new BufferedReader( new InputStreamReader( instream, encoding)); |
| 246 | } |
| 247 | catch( UnsupportedEncodingException uce ) |
| 248 | { |
| 249 | String msg = "Unsupported input encoding : " + encoding |
| 250 | + " for template " + logTag; |
| 251 | throw new ParseErrorException( msg ); |
| 252 | } |
| 253 | |
| 254 | return evaluate( context, writer, logTag, br ); |
| 255 | } |
| 256 | |
| 257 | /** |
| 258 | * Renders the input reader using the context into the output writer. |
| 259 | * To be used when a template is dynamically constructed, or want to |
| 260 | * use Velocity as a token replacer. |
| 261 | * |
| 262 | * @param context context to use in rendering input string |
| 263 | * @param out Writer in which to render the output |
| 264 | * @param logTag string to be used as the template name for log messages |
| 265 | * in case of error |
| 266 | * @param reader Reader containing the VTL to be rendered |
| 267 | * |
| 268 | * @return true if successful, false otherwise. If false, see |
| 269 | * Velocity runtime log |
| 270 | * |
| 271 | * @since Velocity v1.1 |
| 272 | */ |
| 273 | public boolean evaluate( Context context, Writer writer, |
| 274 | String logTag, Reader reader ) |
| 275 | throws ParseErrorException, MethodInvocationException, |
| 276 | ResourceNotFoundException,IOException |
| 277 | { |
| 278 | SimpleNode nodeTree = null; |
| 279 | |
| 280 | try |
| 281 | { |
| 282 | nodeTree = ri.parse( reader, logTag ); |
| 283 | } |
| 284 | catch ( ParseException pex ) |
| 285 | { |
| 286 | throw new ParseErrorException( pex.getMessage() ); |
| 287 | } |
| 288 | |
| 289 | /* |
| 290 | * now we want to init and render |
| 291 | */ |
| 292 | |
| 293 | if (nodeTree != null) |
| 294 | { |
| 295 | InternalContextAdapterImpl ica = |
| 296 | new InternalContextAdapterImpl( context ); |
| 297 | |
| 298 | ica.pushCurrentTemplateName( logTag ); |
| 299 | |
| 300 | try |
| 301 | { |
| 302 | try |
| 303 | { |
| 304 | nodeTree.init( ica, ri ); |
| 305 | } |
| 306 | catch( Exception e ) |
| 307 | { |
| 308 | ri.error("Velocity.evaluate() : init exception for tag = " |
| 309 | + logTag + " : " + e ); |
| 310 | } |
| 311 | |
| 312 | /* |
| 313 | * now render, and let any exceptions fly |
| 314 | */ |
| 315 | |
| 316 | nodeTree.render( ica, writer ); |
| 317 | } |
| 318 | finally |
| 319 | { |
| 320 | ica.popCurrentTemplateName(); |
| 321 | } |
| 322 | |
| 323 | return true; |
| 324 | } |
| 325 | |
| 326 | return false; |
| 327 | } |
| 328 | |
| 329 | |
| 330 | /** |
| 331 | * Invokes a currently registered Velocimacro with the parms provided |
| 332 | * and places the rendered stream into the writer. |
| 333 | * |
| 334 | * Note : currently only accepts args to the VM if they are in the context. |
| 335 | * |
| 336 | * @param vmName name of Velocimacro to call |
| 337 | * @param logTag string to be used for template name in case of error |
| 338 | * @param params[] args used to invoke Velocimacro. In context key format : |
| 339 | * eg "foo","bar" (rather than "$foo","$bar") |
| 340 | * @param context Context object containing data/objects used for rendering. |
| 341 | * @param writer Writer for output stream |
| 342 | * @return true if Velocimacro exists and successfully invoked, false otherwise. |
| 343 | */ |
| 344 | public boolean invokeVelocimacro( String vmName, String logTag, |
| 345 | String params[], Context context, |
| 346 | Writer writer ) |
| 347 | throws Exception |
| 348 | { |
| 349 | /* |
| 350 | * check parms |
| 351 | */ |
| 352 | |
| 353 | if ( vmName == null || params == null || context == null |
| 354 | || writer == null || logTag == null) |
| 355 | { |
| 356 | ri.error( "VelocityEngine.invokeVelocimacro() : invalid parameter"); |
| 357 | return false; |
| 358 | } |
| 359 | |
| 360 | /* |
| 361 | * does the VM exist? |
| 362 | */ |
| 363 | |
| 364 | if (!ri.isVelocimacro( vmName, logTag )) |
| 365 | { |
| 366 | ri.error( "VelocityEngine.invokeVelocimacro() : VM '"+ vmName |
| 367 | + "' not registered."); |
| 368 | return false; |
| 369 | } |
| 370 | |
| 371 | /* |
| 372 | * now just create the VM call, and use evaluate |
| 373 | */ |
| 374 | |
| 375 | StringBuffer construct = new StringBuffer("#"); |
| 376 | |
| 377 | construct.append( vmName ); |
| 378 | construct.append( "(" ); |
| 379 | |
| 380 | for( int i = 0; i < params.length; i++) |
| 381 | { |
| 382 | construct.append( " $" ); |
| 383 | construct.append( params[i] ); |
| 384 | } |
| 385 | |
| 386 | construct.append(" )"); |
| 387 | |
| 388 | try |
| 389 | { |
| 390 | boolean retval = evaluate( context, writer, |
| 391 | logTag, construct.toString() ); |
| 392 | |
| 393 | return retval; |
| 394 | } |
| 395 | catch( Exception e ) |
| 396 | { |
| 397 | ri.error( "VelocityEngine.invokeVelocimacro() : error " + e ); |
| 398 | throw e; |
| 399 | } |
| 400 | } |
| 401 | |
| 402 | /** |
| 403 | * merges a template and puts the rendered stream into the writer |
| 404 | * |
| 405 | * @param templateName name of template to be used in merge |
| 406 | * @param context filled context to be used in merge |
| 407 | * @param writer writer to write template into |
| 408 | * |
| 409 | * @return true if successful, false otherwise. Errors |
| 410 | * logged to velocity log. |
| 411 | * * @deprecated Use |
| 412 | * {@link #mergeTemplate( String templateName, String encoding, |
| 413 | * Context context, Writer writer )} |
| 414 | */ |
| 415 | public boolean mergeTemplate( String templateName, |
| 416 | Context context, Writer writer ) |
| 417 | throws ResourceNotFoundException, ParseErrorException, MethodInvocationException, Exception |
| 418 | { |
| 419 | return mergeTemplate( templateName, ri.getString(INPUT_ENCODING,ENCODING_DEFAULT), |
| 420 | context, writer ); |
| 421 | } |
| 422 | |
| 423 | /** |
| 424 | * merges a template and puts the rendered stream into the writer |
| 425 | * |
| 426 | * @param templateName name of template to be used in merge |
| 427 | * @param encoding encoding used in template |
| 428 | * @param context filled context to be used in merge |
| 429 | * @param writer writer to write template into |
| 430 | * |
| 431 | * @return true if successful, false otherwise. Errors |
| 432 | * logged to velocity log |
| 433 | * |
| 434 | * @since Velocity v1.1 |
| 435 | */ |
| 436 | public boolean mergeTemplate( String templateName, String encoding, |
| 437 | Context context, Writer writer ) |
| 438 | throws ResourceNotFoundException, ParseErrorException, MethodInvocationException, Exception |
| 439 | { |
| 440 | Template template = ri.getTemplate(templateName, encoding); |
| 441 | |
| 442 | if ( template == null ) |
| 443 | { |
| 444 | ri.error("Velocity.parseTemplate() failed loading template '" |
| 445 | + templateName + "'" ); |
| 446 | return false; |
| 447 | } |
| 448 | else |
| 449 | { |
| 450 | template.merge(context, writer); |
| 451 | return true; |
| 452 | } |
| 453 | } |
| 454 | |
| 455 | /** |
| 456 | * Returns a <code>Template</code> from the Velocity |
| 457 | * resource management system. |
| 458 | * |
| 459 | * @param name The file name of the desired template. |
| 460 | * @return The template. |
| 461 | * @throws ResourceNotFoundException if template not found |
| 462 | * from any available source. |
| 463 | * @throws ParseErrorException if template cannot be parsed due |
| 464 | * to syntax (or other) error. |
| 465 | * @throws Exception if an error occurs in template initialization |
| 466 | */ |
| 467 | public Template getTemplate(String name) |
| 468 | throws ResourceNotFoundException, ParseErrorException, Exception |
| 469 | { |
| 470 | return ri.getTemplate( name ); |
| 471 | } |
| 472 | |
| 473 | /** |
| 474 | * Returns a <code>Template</code> from the Velocity |
| 475 | * resource management system. |
| 476 | * |
| 477 | * @param name The file name of the desired template. |
| 478 | * @param encoding The character encoding to use for the template. |
| 479 | * @return The template. |
| 480 | * @throws ResourceNotFoundException if template not found |
| 481 | * from any available source. |
| 482 | * @throws ParseErrorException if template cannot be parsed due |
| 483 | * to syntax (or other) error. |
| 484 | * @throws Exception if an error occurs in template initialization |
| 485 | * |
| 486 | * @since Velocity v1.1 |
| 487 | */ |
| 488 | public Template getTemplate(String name, String encoding) |
| 489 | throws ResourceNotFoundException, ParseErrorException, Exception |
| 490 | { |
| 491 | return ri.getTemplate( name, encoding ); |
| 492 | } |
| 493 | |
| 494 | /** |
| 495 | * Determines if a template is accessable via the currently |
| 496 | * configured resource loaders. |
| 497 | * <br><br> |
| 498 | * Note that the current implementation will <b>not</b> |
| 499 | * change the state of the system in any real way - so this |
| 500 | * cannot be used to pre-load the resource cache, as the |
| 501 | * previous implementation did as a side-effect. |
| 502 | * <br><br> |
| 503 | * The previous implementation exhibited extreme lazyness and |
| 504 | * sloth, and the author has been flogged. |
| 505 | * |
| 506 | * @param templateName name of the temlpate to search for |
| 507 | * @return true if found, false otherwise |
| 508 | */ |
| 509 | public boolean templateExists( String templateName ) |
| 510 | { |
| 511 | return (ri.getLoaderNameForResource(templateName) != null); |
| 512 | } |
| 513 | |
| 514 | /** |
| 515 | * Log a warning message. |
| 516 | * |
| 517 | * @param Object message to log |
| 518 | */ |
| 519 | public void warn(Object message) |
| 520 | { |
| 521 | ri.warn( message ); |
| 522 | } |
| 523 | |
| 524 | /** |
| 525 | * Log an info message. |
| 526 | * |
| 527 | * @param Object message to log |
| 528 | */ |
| 529 | public void info(Object message) |
| 530 | { |
| 531 | ri.info( message ); |
| 532 | } |
| 533 | |
| 534 | /** |
| 535 | * Log an error message. |
| 536 | * |
| 537 | * @param Object message to log |
| 538 | */ |
| 539 | public void error(Object message) |
| 540 | { |
| 541 | ri.error( message ); |
| 542 | } |
| 543 | |
| 544 | /** |
| 545 | * Log a debug message. |
| 546 | * |
| 547 | * @param Object message to log |
| 548 | */ |
| 549 | public void debug(Object message) |
| 550 | { |
| 551 | ri.debug( message ); |
| 552 | } |
| 553 | |
| 554 | /** |
| 555 | * <p> |
| 556 | * Set the an ApplicationAttribue, which is an Object |
| 557 | * set by the application which is accessable from |
| 558 | * any component of the system that gets a RuntimeServices. |
| 559 | * This allows communication between the application |
| 560 | * environment and custom pluggable components of the |
| 561 | * Velocity engine, such as loaders and loggers. |
| 562 | * </p> |
| 563 | * |
| 564 | * <p> |
| 565 | * Note that there is no enfocement or rules for the key |
| 566 | * used - it is up to the application developer. However, to |
| 567 | * help make the intermixing of components possible, using |
| 568 | * the target Class name (e.g. com.foo.bar ) as the key |
| 569 | * might help avoid collision. |
| 570 | * </p> |
| 571 | * |
| 572 | * @param key object 'name' under which the object is stored |
| 573 | * @param value object to store under this key |
| 574 | */ |
| 575 | public void setApplicationAttribute( Object key, Object value ) |
| 576 | { |
| 577 | ri.setApplicationAttribute( key, value ); |
| 578 | } |
| 579 | } |
| 580 | |
| 581 | |
| 582 | |